Consider the rock salt structure in Figure 12.15. What type of structure would result if all the anions were somehow removed, leaving only cations?

Verified step by step guidance

1. Identify the rock salt structure, which is a type of crystal lattice where cations and anions are arranged in a specific pattern.
2. Understand that in the rock salt structure, cations (usually metal ions) and anions (usually non-metal ions) are arranged in a face-centered cubic (FCC) lattice.
3. Consider the scenario where all anions are removed from the structure, leaving only the cations.
4. Recognize that the remaining cations would form a simple cubic lattice, as they originally occupied the octahedral holes in the FCC lattice of the anions.
5. Conclude that the resulting structure, with only cations, would be a simple cubic lattice, which is less stable and less common than the original rock salt structure.

Key Concepts

Rock Salt Structure

The rock salt structure, also known as the face-centered cubic (FCC) lattice, is a common arrangement of ions in ionic compounds like sodium chloride (NaCl). In this structure, cations and anions are arranged alternately in a three-dimensional grid, maximizing the electrostatic attraction between oppositely charged ions. Each cation is surrounded by six anions, forming an octahedral coordination.

Cation Coordination

Cation coordination refers to the arrangement of surrounding anions around a cation in a crystal lattice. In the case of the rock salt structure, each cation is coordinated by six anions. If all anions are removed, the remaining cations would still maintain their spatial arrangement, but the lack of anions would alter the stability and potential structure of the resulting cation-only lattice.

Cation-Only Structures

When only cations remain after the removal of anions, the resulting structure may form a different type of lattice, such as a body-centered cubic (BCC) or a simple cubic structure, depending on the size and charge of the cations. These structures are less common and typically less stable than their ionic counterparts, as the electrostatic forces that stabilize ionic lattices are absent.